Mac OS X only: Donationware application SketchBox provides multi-functional sticky notes for your Mac desktop. Similar to the default Stickies application that's baked into your Mac, SketchBox has tons more functionality, with typing, drawing, and timers built into every sticky. That means you can create a note, type a few lines or doodle an idea, then set a timer to remind yourself to check back with the note later (perfect for quick to-dos). The app also gives you a robust, iPhoto-style organization window for your sticky notes. SketchBox is donationware, Mac OS X only.